Cook Inlet, Alaska
While chartering a fishing trip out with my family in Alaska
last year we happened to motor into Cook Inlet where our guide told us to look
off to our left. We got a good view of Mount
Redoubt, a stratovolcano off the western shore of Cook Inlet in the southern
part of Alaska. Our guide then proceeded
to give us a little history on what is still considered a very active
volcano. Having never seen a volcano
before, we listened with rapt attention.
Mount Redoubt, Alaska
Photo Credit: USGS
Our guide explained to us:
The last major eruption of Mount Redoubt occurred in
2009. There have been four other
eruptions since 1900 occurring in 1902, 1966, 1968, 1989-90. More modern telemetric seismic monitoring has alerted scientists of coming
eruptions signaled often by many mini earthquakes. Historical data
shows that the lava flows and pyroclastic flows (tephra) were largely andesitic
because silicon dioxide compositions were in the 50-60 percentages with the 1966
and 1968 eruptions showing some dacitic tendencies with silica percentages in
the high 60’s. The gases from Mount
Redoubt have been mostly water vapors with some of the gas venting through fumaroles
on the side of the mountain (http://pubs.dggsalaskagov.us/webpubs/dggs/ri/text/ri2011_005.pdf).
Many lava domes have
grown over the past century from moderately viscous flows of lava. Since the lava was not extremely hot, the
lava cooled relatively quickly after leaving the core and created these lava
domes. Mount Redoubt did create many
mudslides because of the very quick melting of snow and glaciers in surrounding
countryside and these lahars produced many safety concerns for
inhabitants. Pyroclastic flows of ash
also created flight risks for pilots after the 1989-90 eruption that caused
grounding of flights for some period of time (https://www.sciencedirect.com/science/article/abs/pii/0377027394900388).
We all thoroughly enjoyed our guided fishing boat experience
and caught many Coho salmon that day with my son catching the largest weighing
35 pounds (no photo available!).
No comments:
Post a Comment